In a refrigerator there typically are provided special drawers or compartments for food items, such as fresh vegetables, where some type of control is provided for adjusting the humidity within the drawer or compartment. Controlling the humidity level in a crisper drawer can lengthen a period of freshness of vegetables. Oftentimes the control is merely a simple slide on the drawer or compartment opening a window or aperture into the space to control the rate at which the humidity in the space will be allowed to dissipate into the remaining space of the refrigerator, which generally has a lower humidity, such as disclosed in U.S. Pat. No. 5,540,492. Othertimes the controls include absorbents and filters, however they do not actively raise the humidity levels in the controlled space, they only capture and control the current humidity levels already available in the environment. These controls are essentially passive in their attempt to control the humidity levels. The crisper drawers continue to lose their moisture level until that level becomes stabilized and in equilibrium with the rest of the refrigeration compartment.
Shape memory polymer is a material referred to herein and refers to a material such as that disclosed in U.S. Pat. Nos. 5,098,776 and 5,139,832.
Various refrigeration compartment constructions are disclosed using moisture permeable files for maintaining a desired humidity level within an enclosure in U.S. Pat. Nos. 6,170,276, 4,788,832, 4,949,847 and 5,918,480.
Other crisper drawer humidity control arrangements are disclosed in U.S. Pat. Nos. 6,463,752, 6,343,477 and 6,223,553.
It would be an advance in the art if there were provided a moisture control barrier that could be actively controlled to maintain a desired moisture level in an enclosure and to add humidity to an interior of the enclosure.